Autonomous vehicles, such as the type configured to transport passengers in an urban environment, may encounter many situations in which an autonomous vehicle ought to alert persons, vehicles, and the like, of the presence of the vehicle in order to avert a potential collision or an approach of the vehicle within an unsafe distance of an external object, such as a pedestrian for example.
As one example, in a conventional vehicle piloted by a human being, a pedestrian who crosses the road in front of the vehicle may be jaywalking or may not be paying attention to the approach of the vehicle. In some scenarios, the driver of the vehicle may decide to use the vehicle's horn to alert the pedestrian. However, a horn will typically have an acoustic radiation pattern that is sub-optimal and may not be sufficient to warn the pedestrian that the horn being honked is intended for him/her. Instead, other pedestrians or other drivers in the vicinity of the vehicle may believe the horn is being honked at them. Moreover, a pattern of the sound waves emitted by the horn may make it difficult to localize the source of the horn. From the perspective of the pedestrian, the horn may be perceived as coming from another vehicle. Furthermore, the horn may cause the pedestrian to look in a direction other than the direction of the vehicle that generated the horn honk, thereby potentially distracting the pedestrian from the actual source of the horn.
Finally, autonomous vehicles may share the road with other vehicles and persons. However, autonomous vehicles may be difficult to audibly detect due to low levels of emitted noise from an electric and/or hybrid propulsion system (e.g., lack of combustion engine noise and/or lower levels of tire noise).
Therefore, in situations where the autonomous vehicle intends to issue an audible alert, a targeted and/or more socially acceptable sound source (e.g., less rude than a horn) may be desirable. Accordingly, there is a need for systems, apparatus and methods for implementing focused acoustic alerts from robotic vehicles.
Although the above-described drawings depict various examples of the invention, the invention is not limited by the depicted examples. It is to be understood that, in the drawings, like reference numerals designate like structural elements. Also, it is understood that the drawings are not necessarily to scale.